Wristify thermoelectric bracelet makes heating and cooling personal


October 24, 2013

The Wristify thermoelectric bracelet being put to the test at MIT's MADMEC (Photo: Franklin Hobbs)

The Wristify thermoelectric bracelet being put to the test at MIT's MADMEC (Photo: Franklin Hobbs)

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Most bracelets aren't likely to alter your temperature too much either way, but the Wristify isn't most bracelets. Developed by four MIT engineering students, the Wristify works on the principle that heating or cooling the skin on one part of the body can make the entire body feel warmer or colder. By creating a personal heating and cooling device, the Wristify team ultimately hopes to cut the amount of energy currently used to heat or cool entire buildings.

Currently at working prototype stage, the Wristify resembles a wristwatch with a custom copper-alloy-based heat sink. This is is attached to an automated control system that automatically adjusts the intensity and duration of thermal pulses that are delivered to the heat sink based on readings from thermometers integrated into the device that measure external and body temperature. The prototype can run for up to eight hours thanks to a lithium polymer battery.

While developing Wristify, the team found that minute, rapid changes in temperature on one part of the human body can affect the whole body. They discovered that a change of 0.1° C (0.18° F) a second is the minimum rate required to make the entire body feel several degrees warmer or colder. The current prototype, which is the team's 15th, is capable of a rate of change of up to 0.4° C (0.7° F) per second.

The team believes that by providing individuals with a personal cooling and heating device, the Wristify has the potential to cut the amount of energy currently used to cool and heat the space within buildings. They say that adjusting the temperature of just one building by 1° C (1.8° F) can consume around 100 kWh per month, so while the device won't be able to completely replace a building's heating and cooling system, it could allow for significant savings.

“Buildings right now use an incredible amount of energy just in space heating and cooling. In fact, all together this makes up 16.5 percent of all US primary energy consumption. We wanted to reduce that number, while maintaining individual thermal comfort,” says Sam Shames, who co-invented the Wristify with Mike Gibson, David Cohen-Tanugi, and Matt Smith. “We found the best way to do it was local heating and cooling of parts of the body.”

The team recently took out the US$10,000 first prize in MIT's annual Making And Designing Materials Engineering Competition (MADMEC). They plan to use the money to continue development of the device. This will include using more advanced algorithms to improve the automation of the thermal pulses.

Source: MIT News, Wristify

About the Author
Darren Quick Darren's love of technology started in primary school with a Nintendo Game & Watch Donkey Kong (still functioning) and a Commodore VIC 20 computer (not still functioning). In high school he upgraded to a 286 PC, and he's been following Moore's law ever since. This love of technology continued through a number of university courses and crappy jobs until 2008, when his interests found a home at Gizmag. All articles by Darren Quick

How skin to breathe? If you frozen just wear warm cloth LOL.


It's just a peltier, heatsink and watch strap. Why did they need 15 iterations of that?

It could also be made 50-75% smaller and still have the same effect. And be placed at a more strategic position, with more blood flow. Btw. I don't see a temperature sensor on any of the images. Hardware-wise this seems like a hobbyist afternoon project, it's only the fine tuning that might take some more time.


this would be awesome for endurance athletes! Its a billion dollar market. Racing in heat is always an issue for most and if they could keep their temperature down, it would be a HUGE advantage in terms of caloric savings! I hope this market gets explored.

Mark McGraw

It's a neat idea -- just from personal experience, running cold water over your wrist on a hot day makes you feel substantially cooler. But it appears that this is simply tricking the mind into making you feel cooler, rather than actually lowering body temperature...? I can see this could be a little dangerous. And considering the public resistance to just wearing warmer clothes, even with rapidly increasing energy costs, I struggle to see people rushing to strap heatsinks to themselves. That said, I'd probably still buy one, if just out of curiosity.


heavy sharp dangerous ugly would not cool or heat you anyway during exercise

i;d pay about $5 for it

how much is it, about $1000?

my wife won;t even put on a sweater she would be have to have a complete personality change to put this thing on..


Larry English

All the same, I want one!

B Peter Brandt-Sorheim

Want to be cool and look weird at the same time? Take a couple of old CPU heatsinks with fans and fashion something to hold them to either side of your neck, over the carotid arteries and jugular veins.

Connect a 9V battery to the fans and you'll feel like you've strapped a couple small blocks of ice to your neck.

Gregg Eshelman

I already have an item that can make me feel warmer without increasing energy consumption. It's called a sweater.

As for cooling, the Sharper Image and other gadget stores have sold powered evaporative personal cooling collars for many years. Much less likely to be damaged than a wrist-mounted device. Or make an unpowered version using sodium polyacrylate or something similar as a gel inside a fabric cover.


I would love this and all menopausal women will thank you!

Sara Mccracken

I worked with peltier thermoelectrics for about ten years, and one thing which is still true to this day is inefficient of energy these devices are!...The technology has along way to go before they can be used effectively and cost$ to purpose of it's use in any manner worthy of.

Sam Joy

This looks like it's nothing more than a Peltier Piezo device. You can buy these online all day long for under $10...Add a monostable timer and viola! same thing!


Developing a good waste heat recycler for the air conditioner or a high R value paint would save more energy than this. But for personal cooling at outdoor events in might be great but I suspect a fan in the hat might work better.


I wish someone would actually make one of these. The first patent was filed in the 1920's and it was basically a device that hold dry ice on your wrist and since then many have tried but none have ever come out. I work outside in the 100° F weather and I'd love a device that keeps my temp down.

Also, those colar things that are a 'personal air conditioner' don't work. They for office people that work in offices set at 50° F and complain it is too hot not people working in hot conditions.


Interesting, but far from new.

Looks very like a device I saw a couple of years ago at Media Labs Melbourne. They had it communicating with Twitter, and I got to wear it and sense a jolt of coldness as it parsed messages from a web service.

I think weight/bulk and power requirements are matters to be improved. That said, it's encouraging, and we get useful haptic feedback from the vibration mode in smartphones.


I'm pretty sure they wouldn't have won a $10,000 MIT prize if they'd simply gone out and purchased a $10 peltier and a timer and soldered them together in an afternoon, I'm pretty sure a lot more research and tweaking has gone into this. If they did, then I'm off to Jaycar tomorrow to score me $10,000 for $10!

This would be fantastic for those of us that live in the tropics (ie where I live, Far North Queensland, Australia). It's all well and good for those people in cooler climates to say 'you can put on a sweater for free' but when you wear shorts, t-shirt & thongs 365 days a year whilst having the air-conditioner on inside 365 days a year it's pretty hard to do much else to cool down other than have a few refreshing ales!

If they could shrink this down and incorporate it into a wrist watch that would be fantastic! Would be so great for when you're outside trying to do some gardening. Or working on the car. Or fixing the house. In the tropics...


How about a stirling cycle attached to your wrist attached to your phone. Your body and ambient air charge your phone and cool you down.

Andrew Zuckerman

This is very interesting and I would like to see more on this. I do believe that if one part of the body is cold or hot it makes the rest of the body that way. When my feet or head are cold it makes my whole body cold. I love all the new technology that is coming out and it would be nice to see an advancement with heating and cooling in Chicago IL as well. Sometimes it just gets too cold there in the winter.

Brandie Black

Brilliant, I would like to add the reverse feature to generate power by exchanging heat. (like Sterling Motor) Would that be great not only to cool or heat as you like but also to generate your own power for that? Keep going. Frank


so it took a team of 4 MIT students to make what I made in a weekend with an arduino should I feel smarter?

Will Meyers
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